Zero turning radius mowers are well known in the art. Typically, such mowers are provided with twin drive levers that are manipulated by the operator to regulate the speed, turning and forward or reverse operations of the mower. Reversible hydraulic motors associated with the ground-engaging drive wheels are supplied with hydraulic fluid in variable amounts by pumps that are linked to the drive levers. Steering of the machine is accomplished by speeding up or slowing down one of the hydraulic motors relative to the other and, in some instances by reversing the direction of one of the motors relative to the other. The drive levers are movable independently of one another along fore-and-aft paths of travel to accomplish such control.
It is also known in the art to construct the control system in such a way that the drive levers can be swung out laterally away from one another to widespread positions when the controls are in neutral so the operator can dismount the machine. In U.S. Pat. No. 6,434,917, for example, the drive levers also set parking brakes for the drive wheels when the levers are swung out to their widespread positions.
In the present invention the retaining mechanism for each drive wheel, such as a parking mechanism or a safety brake, is applied through the use of a single park lever separate and apart from the two drive levers. The park lever may only be operated when the two drive levers are in the neutral mode and have been swung out to their widespread positions. Once the park lever is engaged, an interlock structure mechanically blocks return of the drive levers from their widespread positions to their fore-and-aft paths of operating travel. Unless the drive levers are in their widespread positions and the mower is in park, the engine of the machine cannot be started once it has been turned off. A control switch forming a part of an electrical control circuit for the mower is actuated by structure operably coupled with the park lever so that the switch is actuated by movement of the park lever to the park position. Although the drive wheels are provided with two separate park mechanisms, they are actuated simultaneously by the single park lever.